JP4499739B2 - Multi-mode and multi-band RF transceiver and associated communication method - Google Patents

Description

(Cross-reference with related applications)
This application is a continuation-in-part of US Patent Application No. 60 / 48,737, filed Dec. 4, 2003.

  The present invention relates to RF transceivers, and more particularly to multimode and multiband RF transceivers such as GSM / EDGE and WCDMA dual mode and multiband mobile phones, and related communication methods.

  Over the past decade, wireless communication systems have made tremendous progress. Various communication systems such as GSM and CDMA have been introduced into the mobile phone market, and various wireless communication functions have been realized. The mobile phone includes a wireless RF transceiver that transmits / receives wireless signals. An RF transceiver typically includes a phase-locked loop (PLL) as a frequency synthesizer that generates a local oscillator (LO) carrier signal.

  In general, a standard multi-mode or multi-band RF transceiver needs to include two or more LOs to generate multiple carrier signals for different bands or system modes, and thus two or more PLLs. The need for inclusion increases the chip size, which increases system complexity and manufacturing costs.

  The RF transceiver includes a transmitter that emits wireless communication signals. Please refer to FIG. This is a functional block diagram of the wireless transmitter 10 according to the prior art. The basic function of this transmitter 10 is to modulate or decode baseband information on a high frequency sinusoidal carrier that may be radiated by a transmit antenna, for example, audio, video data or other information. The reason for this is that higher frequency signals can be radiated more efficiently and the RF band can be used more effectively than directly radiating baseband signals. The transmitter 10 includes a first local oscillator (LO) 12 that generates a first LO signal, and an intermediate frequency (IF) in which an I / Q baseband signal is normally 10 to 100 MHz by the first LO signal. An I / Q modulator 14 that modulates the signal, a first bandpass filter 16 that passes frequency components in a narrow passband, but does not pass frequency components such as noise outside the passband, and a second By mixing the IF signal with the second LO 18 that generates the LO signal and the IF signal, the IF signal output from the first bandpass filter 16 is converted into the sum of the IF signal and the second LO signal. A mixer 20 for up-conversion to the difference, a second band-pass filter 22 connected to the mixer 20 to pass only the sum of the IF signal and the second LO signal, and a second band-pass Includes a power amplifier 24 to increase the power of the signal output from Iruta 22, a signal having a power amplified by the power amplifier 24, a transmitting antenna 26 which converts the wave propagating electromagnetic space, the.

  Both the first LO 12 and the second LO 18 are constituted by a PLL having a voltage controlled oscillator. This PLL feedback control circuit allows the voltage controlled oscillator to accurately track the phase of the stable reference oscillator. The two-stage transmitter 10 applied to the WCDMA communication system has advantages in that LO pull-in is reduced, LO feedthrough is low, and crosstalk between I / Q channels is reduced. .

RF transceivers include not only transmitters but also receivers. Please refer to FIG. This is a functional block diagram of a superheterodyne receiver 30 according to the prior art. The receiver 30 amplifies an extremely weak received signal received by the antenna 32, the third band pass filter 34, and the antenna 32, and minimizes noise power applied to the received signal. A noise amplifier 36, a third LO 38 for generating a third LO signal , a second mixer 40 for down-converting the signal sent from the low noise amplifier 36 into an IF signal, and a second LO connected to the second mixer 40 4 bandpass filter 42, a fourth LO 44 that generates a fourth LO signal , and a fourth bandpass filter 42 connected to the fourth bandpass filter 42 and the fourth LO 44. And a demodulator 46 for receiving an I / Q baseband signal from among the signals.

  According to FIG. 1 and FIG. 2, the mobile phone transceiver has four sophisticated LOs.

  Due to intense competition in the mobile phone market, there is a strong desire to reduce the number of parts, size, weight, and cost of transmitter 10 and even receiver 30. Thus, direct conversion transmitters applied to GSM communication systems are of great interest because, in this type of transmitter topology, the first LO 12 of the transmitter 10, the first bandpass filter 16 and This is because the second bandpass filter 22 is omitted.

  If multimode or multiband RF transceivers can share a single frequency synthesizer capable of generating various carrier signals without significantly affecting the quality of signal transmission and reception, the above disadvantages will be overcome. . Such an RF transceiver has a simple structure and low cost. Please refer to FIG. This is a functional block diagram of a direct conversion transmitter 50 according to the prior art. A set of I / Q signals enters the fifth bandpass filter 52 and the sixth bandpass filter 54, respectively, and then mixed and orthogonalized with the LO signal generated by the fifth LO (PLL) 56. The The orthogonalized I / Q signal enters the power amplifier 58 and is amplified in power, and transmitted by the transmitting antenna 60.

  Despite having the advantage of containing minimal components, additional topology for isolation is required because transmitter 50 can still be adversely affected by LO input pull-in problems. Furthermore, the PLL, mixer and adder of transmitter 50 must be elaborately designed to have very low phase noise, increasing the complexity of IC circuit design and semiconductor manufacturing processes.

  Accordingly, it is a primary object of the present invention as set forth in the appended claims to provide a multimode and multiband RF transceiver and associated wireless communication method with minimal components and ease of manufacture. is there.

The multi-mode communication system according to the present invention described in the claims includes an oscillator that generates a vibration signal having a frequency corresponding to the control signal by determining the control signal, and is electrically connected to the oscillator. A first frequency divider for generating a comparison signal having a frequency equal to a product of the frequency of the vibration signal and the frequency division ratio by determining the vibration signal and the frequency division ratio, and the first frequency divider electrically And a frequency modulator operable to operate in either a modulation mode or a constant frequency mode. When operating in the modulation mode, the frequency modulator modulates the frequency division ratio based on the content of the first communication signal so that the vibration signal can change its frequency according to various contents of the first communication signal. To do. When operating in the constant frequency mode, the frequency modulator allows the vibration signal to keep its frequency constant by keeping the division ratio unchanged. The communication system further includes a frequency phase detector that is electrically connected to the first frequency divider and adjusts the control signal based on the frequency of the comparison signal, and a transmission module that transmits a communication signal output from the communication system. A switch capable of transmitting a vibration signal to the transmitting module when the frequency modulator is operating in the modulation mode or to the receiving end when the frequency modulator is operating in the constant frequency mode; And a communication module. The second communication module is electrically connected to the reception end, mixes the second communication signal with the reception signal received at the reception end, and generates a third communication signal holding the reception signal. Including a first mixer.

  It is an advantage of the present invention described in the claims that the multi-mode communication system can be applied to various communication systems with a minimum number of components.

  These and other objects of the present invention will become apparent to those skilled in the art after reading the following preferred embodiments illustrated by the figures.

  Please refer to FIG. This is a functional block diagram of a preferred embodiment multimode and multiband RF transmitter 70 according to the present invention. This RF transmitter 70 is applicable to GSM, EDGE, CDMA, WCDMA, CDMA2000, WLAN communication system, and the like. The transmitter 70 determines the fractional-N frequency synthesizer 72 and the transmission end 76 electrically connected to the frequency synthesizer 72 by determining a signal transmitted from the frequency synthesizer 72. A first switch 74 that can be selectively connected to the receiving end 78, 80 or 82, a GSM-900 transmission module 84 that is electrically connected to the first receiving end 78, and a second receiving end 80. A GSM-1800 transmission module 86 that is electrically connected to the WCDMA module, and a WCDMA (WLAN 802.11b or WLAN 802.11g) module 88 that is electrically connected to the third end 82.

The frequency synthesizer 72 uses a carrier wave (CW) (local oscillation wave) having a constant frequency f _vco for up-conversion of the first baseband signal T _{x1 in} the first mode, or in the second mode. sigma based on the second baseband signal T _x2 - a RF signal whose frequency is changed by the frequency division ratio of the fractional -N divider 94 controlled by the delta modulator 90, it is possible to selectively produce Is. The frequency synthesizer 72 is electrically connected to the VCO 92 and a voltage controlled oscillator (VCO) 92 that generates a vibration signal having a frequency corresponding to the control signal based on the control signal, and generates a vibration signal and a frequency dividing ratio. The first fractional-N frequency divider 94 that generates a comparison signal having a frequency equal to the product of the frequency of the vibration signal and the frequency division ratio is electrically connected between the first frequency divider 94 and the VCO 92. Are connected to each other and electrically connected to a frequency phase detector 96 for adjusting the control signal based on the frequency of the comparison signal and a first frequency divider 94 to modulate the T _x2 data to obtain a frequency division ratio. A sigma-delta modulator 90 which is a frequency modulator.

  A fractional-N divider 94 can be used with the adder / accumulator to selectively divide the input signal by either N or N + 1 based on the overflow output from the adder / accumulator. Fraction-N dividers are well known in the art and will not be described in further detail.

  The GSM-900 transmission module 84 includes a GSM-900 antenna, a low-pass filter, a power amplifier (PA), and a PA driver. The GSM-1800 transmission module 86 has a structure similar to the GSM-900 transmission module 84.

In FIG. 4, the WCDMA module 88 includes a second frequency divider 98 that _divides a signal received by the third receiving end 82, and an I / Q modulator 100 that modulates T _x1 data (WCDMA / EDGE). A heterodyne structure including a first mixer 102 that mixes the modulated signal from the I / Q modulator 100 with a signal received by the third receiving end 82, and an antenna 104 that emits the mixed signal. Have.

When the RF transmitter 70 is operating in the GSM mode, the frequency synthesizer 72 is controlled to generate an RF signal based on the T _x2 data input to the sigma delta modulator 90 and the first switch 74. Is controlled to electrically connect the transmitting end 76 to either the first receiving end 78 or the second receiving end 80, and finally the GSM-900 transmitting module 84 or GSM-1800 transmitting module 86 is RF Send a signal.

In addition, when the RF transmitter 70 is operating in the WCDMA mode, the frequency synthesizer 72 is controlled to generate a CW (local oscillation wave) because the division ratio of the fractional-N divider is constant. The first switch 74 is controlled to electrically connect the transmitting end 76 to the third receiving end 82. The second frequency divider 98 of the WCDMA module 88 divides the CW and generates a frequency- _divided signal having the second frequency f _vco / N ₂ . The modulator 100 modulates the T _x1 data with the frequency-divided signal, and then generates a modulation signal that is an IF signal. The first mixer 102 mixes the modulated signal with a CW having a first frequency f _vco to generate two mixed RF signals having two types of frequencies, f _vco ± f _vco / N ₂ . . Finally, antenna 104 emits one of two mixed RF signals.

In the related communication method according to the present invention, (a) in the GSM mode, an RF signal is generated using a fractional-N frequency synthesizer 72 whose division ratio is controlled based on T _x2 data, and then the RF signal is And (b) generating a CW tone having a constant frequency by keeping the division ratio of the fractional-N frequency synthesizer 72 constant in the WCDMA mode, and (c) a second frequency division. The frequency-divided signal generated by the generator 98 is mixed with the modulation signal generated by the I / Q modulator 100 based on the T _x1 data, and then the T _x1 signal is converted to a frequency of f _vco ± f _vco / N ₂ . And (d) emitting the mixed signal from the antenna 104.

  The transceiver includes both a transmitter and a receiver. Please refer to FIG. This is the RF transceiver 400 of the second embodiment according to the present invention. The RF transceiver 400 can operate in the GSM mode to transmit / receive data asynchronously, or operate in the WCDMA mode to transmit / receive data synchronously.

In addition to the frequency synthesizer 72 and the WCDMA module 88, the transceiver 400 further includes an RF receiver module 402. When the transceiver 400 is controlled to operate in the WCDMA mode, the second switch 404 connects the frequency synthesizer 72 to the WCDMA module 88 and the RF receiving module 402 at the same time, so that the first frequency from the frequency synthesizer 72 is The CW tone with f _vco is used by the WCDMA module 88 and the RF receiving module 402. Note that transceiver 400 includes only one LO.

  The RF receiving module 402 divides the CW (local oscillation wave), mixes the CW tone with the frequency-divided CW tone, and a third frequency divider 406 that generates the frequency-divided CW. It includes a second mixer 408 to be generated, a third mixer 410 that down-converts the radio signal received by the antenna 104, and a demodulator 412 that demodulates the down-converted signal into an I / Q signal.

  The RF receiver module 402 can also function as a GSM receiver. In the GSM reception mode, the second switch 404 connects the frequency synthesizer 72 that provides a local oscillation wave to the RF reception module 402 in order to keep the frequency division ratio constant. Thereby, the RF receiving module 402 down-converts the input RF signal based on the local oscillation wave.

As shown in FIG. 6 which is a functional block diagram of the RF transmitter 120 of the third embodiment according to the present invention, the second frequency divider 98 of the WCDMA module 88 of the transmitter 70 shown in FIG. Instead of being connected to the third receiving end 82 of one switch 74, it may instead be electrically connected directly to the frequency synthesizer 72. In the transmitter 120, the second frequency divider 98 is not directly connected to the third receiving end 82 of the first switch 74 like the second frequency divider 98 of the communication system 70, but directly to the frequency. Except for being electrically connected to the synthesizer 72, it has a structure similar to the transmitter 70 shown in FIG.

Please refer to FIG. This is a functional block diagram of the RF transmitter 140 of the fourth embodiment according to the present invention and has a homodyne structure. Transmitter 140 also includes a WCDMA module 142 of transmitter 140 that includes a mixer that mixes the CW from frequency synthesizer 72 with another CW to generate additional CWs used by I / Q modulator 100. Except for this, the transmitter 70 has a similar structure.

  In contrast to the prior art, the present invention is a dual mode (GSM / EDGE and WCDMA / WLAN802.11b and 11g) and of course a variety of frequencies (GSM900 and 1, 800) capable of operating in multi-mode and multi-band RF transceivers and associated wireless communication methods, resulting in reduced system complexity and integrated circuit manufacturing costs. .

  Those skilled in the art will readily appreciate that numerous changes and modifications of the apparatus and method are possible while maintaining the disclosure of the present invention. Accordingly, the above disclosure should be construed as limited only by the metes and bounds of the appended claims.

It is a functional block diagram of the radio transmitter by a prior art. It is a functional block diagram of the receiver by a prior art. It is a functional block diagram of the direct conversion transmitter by a prior art. FIG. 2 is a functional block diagram of a preferred embodiment RF transmitter according to the present invention. It is a functional block diagram of RF transceiver of a 2nd embodiment by the present invention. It is a functional block diagram of RF transmitter of a 3rd embodiment by the present invention. It is a functional block diagram of RF transmitter of a 4th embodiment by the present invention.

Explanation of symbols

70 Transmitter 72 Frequency Synthesizer 90 Sigma-Delta Modulator 92 Voltage Controlled Oscillator (VCO)
94 first frequency divider 96 frequency phase detector 74 first switch 76 transmission end 78, 80, 82 reception end 84 GSM-900 transmission module 86 GSM-1800 transmission module 88 WCDMA module 98 second frequency divider 100 I / Q modulator 102 First mixer 104 Antenna 400 Transceiver 402 RF receiving module 406 Third frequency divider 408 Second mixer 410 Third mixer 412 Demodulator 404 Second switch 120 Transmitter 140 Transmitter 142 WCDMA Module

Claims (6)

Generating a vibration signal having a frequency corresponding to the control signal according to the control signal;
Generating a comparison signal having a frequency equal to a product of the frequency of the vibration signal and the frequency division ratio based on the vibration signal and the frequency division ratio;
Modulating the division ratio, and, optionally, in the modulation mode, by modulating the division ratio based on the first communication signal, so that before Symbol vibration signal can change its frequency, Alternatively, in the constant frequency mode, by keeping the frequency dividing ratio unchanged, the vibration signal can make the frequency constant;
Adjusting the control signal based on the frequency of the comparison signal;
Selectively sending the vibration signal by a switch to the first transmission module when operating in the modulation mode or to the second transmission module when operating in the constant frequency mode;
A step of said reception signal received by the second transmitting module is mixed with the vibration signal is a constant frequency in the predetermined frequency mode, to produce a mixed signal obtained by holding the received signal,
Including
The first transmission module operates in the modulation mode;
The second transmission module operates in the constant frequency mode;
The multi-mode communication method, wherein the first communication signal is a baseband signal . The method of claim 1 , further comprising dividing the vibration signal sent to the second transmission module . The method of claim 1 , wherein the vibration signal having a constant frequency in the constant frequency mode is a continuous wave (CW). A multi-mode communication system,
An oscillator that generates a vibration signal having a frequency corresponding to the control signal according to the control signal;
A first frequency divider electrically connected to the oscillator for generating a comparison signal having a frequency equal to a product of the frequency of the vibration signal and the frequency division ratio based on the vibration signal and the frequency division ratio;
The first a divider frequency modulator electrically connected modulating the division ratio, selectively, modulated in modulation mode, the division ratio based on the first communication signal by, so before Symbol vibration signal may change its frequency or at a constant frequency mode, by keeping unchanged the division ratio, the vibration signal is to be the frequency constant A frequency modulator, and
A frequency phase detector electrically connected to the first divider and the oscillator for adjusting the control signal based on the frequency of the comparison signal;
A first communication module comprising:
A first transmission module and a second transmission module for transmitting a communication signal to be output from the multi-mode communication system;
Selectively to the first transmission module when the frequency modulator is operating in the modulation mode, or to the second transmission module when the frequency modulator is operating in the constant frequency mode; a switch, capable of sending a vibration signal,
The second transmitting module, wherein the second transmission module electrically connected, the constant in the frequency mode vibration signal is constant frequency is mixed with the received signal received by the second transmitting module, the received signal look including a first mixer for generating a mixed signal obtained by holding a
The first transmission module operates in the modulation mode;
The second transmission module operates in the constant frequency mode;
The multi-mode communication system, wherein the first communication signal is a baseband signal . The second transmission module is electrically connected between the second transmission module and the switch, and divides the frequency of the vibration signal sent from the switch to the second transmission module . The communication system according to claim 4 , further comprising a frequency divider. The second transmission module further comprises a communication system according to claim 4, wherein a local oscillator for generating the oscillation signal is a continuous wave (CW) having a constant frequency.

Images